US4628978A - Pneumatic radial tires - Google Patents

Pneumatic radial tires Download PDF

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Publication number
US4628978A
US4628978A US06/700,344 US70034485A US4628978A US 4628978 A US4628978 A US 4628978A US 70034485 A US70034485 A US 70034485A US 4628978 A US4628978 A US 4628978A
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US
United States
Prior art keywords
cord
carcass
polyester fiber
tension
fiber
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US06/700,344
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English (en)
Inventor
Isamu Imai
Kazuo Oshima
Norio Inada
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Bridgestone Corp
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Bridgestone Corp
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Publication date
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Assigned to BRIDGESTONE TIRE COMPANY LIMITED reassignment BRIDGESTONE TIRE COMPANY LIMITED ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: IMAI, ISAMU, INADA, NORIO, OSHIMA, KAZUO
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C9/00—Reinforcements or ply arrangement of pneumatic tyres
    • B60C9/0042—Reinforcements made of synthetic materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C9/00—Reinforcements or ply arrangement of pneumatic tyres
    • B60C9/02—Carcasses
    • B60C9/04—Carcasses the reinforcing cords of each carcass ply arranged in a substantially parallel relationship
    • B60C9/08—Carcasses the reinforcing cords of each carcass ply arranged in a substantially parallel relationship the cords extend transversely from bead to bead, i.e. radial ply
    • D—TEXTILES; PAPER
    • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
    • D02G—CRIMPING OR CURLING FIBRES, FILAMENTS, THREADS, OR YARNS; YARNS OR THREADS
    • D02G3/00—Yarns or threads, e.g. fancy yarns; Processes or apparatus for the production thereof, not otherwise provided for
    • D02G3/44—Yarns or threads characterised by the purpose for which they are designed
    • D02G3/48—Tyre cords
    • D—TEXTILES; PAPER
    • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
    • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
    • D10B2331/00—Fibres made from polymers obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polycondensation products
    • D10B2331/04—Fibres made from polymers obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polycondensation products polyesters, e.g. polyethylene terephthalate [PET]

Definitions

  • This invention relates to high-durable pneumatic radial tires using polyester fiber cords as a carcass ply.
  • polyester fiber cord is best in the general-purpose properties in view of mechanical fatigue property, stability on moisture, corrosion resistance, adhesion property, high modulus of elasticity and creep resistance. Lately, therefore, the use of the polyester fiber cord as the carcass material successively increased and further the modification of the polyester fiber into higher modulus one and the like are more performed.
  • polyester fiber cords the heat shrinkage of which are small even if the cord is subjected to high tension treatment after the spinning under high stress, have recently begun to be applied to tires as disclosed, for example, in U.S. Pat. Nos. 4,101,525 and 4,195,052 together with Japanese Patent laid-open No. 57-154,410.
  • post-cure inflation means a procedure of setting a tire under a predetermined internal pressure over a predetermined period after the vulcanization building.
  • a pneumatic radial tire comprising a carcass composed of at least one ply containing polyester fiber cords embedded in rubber, said polyester fiber cord having such micro properties as a fiber that an intrinsic viscosity is 0.75-0.97, a specific gravity is 1.365-1.398 and number of terminal carboxyl groups is not more than 20, and having such properties as a cord that a twist constant NT defined by the following equation (1) is 0.4-0.6 and an elongation ⁇ E n under a tension of 2 g/denier (hereinafter abbreviated as g/D) in the cord produced through a post-cure inflation (hereinafter abbreviated as PCI) holding an inner temperature of a shoulder portion at at least 95° C.
  • g/D 2 g/denier
  • PCI post-cure inflation
  • N is a twisting number per 10 cm of cord length
  • D is a total denier of cord and ⁇ is a specific gravity of fiber
  • N' is number of carcass plies, i is a cord count of carcass ply in crown center (cords/cm)
  • R m is a maximum radius of carcass line as shown in FIG. 1 (cm)
  • R v is an average value of R m and R r representing a radius of a rim as shown in FIG. 1);
  • heat shrinkage ⁇ S means a shrinkage (%) after the cord is heated at 177° C. for 30 minutes.
  • the reason why the polyester fiber is necessary to satisfy the micro properties within the above defined ranges is due to the fact that when the intrinsic viscosity is less than 0.75, the heat shrinkage is small but the tensile strength and flex fatigue resistance lower to such an extent that they are unsuitable as a ply material for tire, while when the intrinsic viscosity exceeds 0.97, the heat shrinkage is large to adversely affect the dimensional stability, and further when the number of terminal carboxyl groups exceeds 20, the heat aging resistance of the cords embedded in rubber deteriorates to such an extent that the cords are unsuitable as a cord for usual tires.
  • the polyester fiber has a birefringence ⁇ N of 165 ⁇ 10 -3 -195 ⁇ 10 -3 .
  • ⁇ N is less than 165 ⁇ 10 3 , the heat aging resistance after the heat treatment and the tensile strength are insufficient, while when ⁇ N exceeds 195 ⁇ 10 -3 , sufficiently stable crystalline.amorphous state is not obtained.
  • the twist constant NT when the twist constant NT is less than 0.4, the flex fatigue resistance is extremely deteriorated and the resulting cords are unsuitable as a ply material for tire, while when NT exceeds 0.6, the satisfactory tensile strength and modulus of elasticity of the cord are not obtained.
  • the temperature of the polyester fiber cord is a temperature lower than the glass transition temperature of polyester, so that it is difficult to produce orientation of molecular chain in the amorphous portion of the polyester fiber even when a tension is applied to the cord and also the elongation under a tension of 2 g/D cannot be made to not more than 4.5%.
  • the internal pressure P is less than 0.5D. ⁇ 10 -3 , a sufficient tension cannot be applied to the cord and ⁇ E n of not more than 4.5% is not obtained, while when P exceeds 2.5D. ⁇ 10 -3 , there is caused a risk of breaking cords.
  • ⁇ E n of not more than 4.5% and ⁇ E n + ⁇ S of not more than 8.0% are obtained by restricting the micro properties of the polyester fiber, the twist count NT of the polyester fiber cord and the conditions of PCI as described above. Therefore, when the polyester fiber cords having such properties are applied to the carcass and belt of the tire, the stress concentration at ends of the carcass and belt is suppressed to prevent the occurrence of separation failure at these ends, whereby the durability of the tire can be improved considerably.
  • the high-tension heat treatment is preferably carried out at a temperature of 230°-255° C. under a tension of 0.15-1.0 g/D so as to obtain ⁇ E n + ⁇ S of not more than 8.0% after an adhesive is applied to the cord in order to provide a good adhesion to rubber.
  • FIG. 1 is a schematic radial half section of an embodiment of the radial tire according to the invention.
  • FIG. 2 is a graph showing a relation between the internal pressure in PCI and ⁇ E n .
  • Radial tires haviing tire sizes of 165 SR 13 and 185 SR 14 were manufactured by using as a carcass ply cords of polyester (polyethylene terephthalate) fibers produced by usual spinning method and high-stress spinning method and then subjected to an indoor drum test wherein the tire was continuously run on a drum at a speed of 65 km/hr under a JIS 200% load over a distance of 20,000 km.
  • Table 1 are shown properties of the polyester fibers produced by the usual spinning and high-stress spinning methods, twisting structure of cord composed of such polyester fiber, properties of the cord after high-tension heat treatment, ⁇ E n and ⁇ S of the cord after PCI, and test results on the tire with a size of 165 SR 13.
  • the test results on the tire with a size of 185 SR 14 as well as the properties of the polyester fibers and their cords are shown in the following Table 2.
  • the properties of the fiber were measured as follows.
  • the measurement was performed in a mixed solvent of carbon tetrachloride and tetrachloroethane with a weight ratio of 1:1 at a temperature of 25° C.
  • ⁇ N It was measured by a polarizing microscope using a Berek compensator.
  • the measurement was performed by dissolving a predetermined amount of polyester fiber into a predetermined amount of benzyl alcohol at 220° C., cooling in chloroform and titrating with sodium hydroxide.
  • Examples 1 and 2 satisfy all features of the invention, particularly ⁇ E n of not more than 4.5% and ⁇ E n + ⁇ S of not more than 8.0% in the cord after PCI and do not fail even after the running over 20,000 km in the indoor drum test and are very small in the crack at belt end.
  • Comparative Examples 1, 6 and 7 do not satisfy the fiber properties among the features of the invention, while NT in Comparative Example 5 is less than 0.4.
  • Comparative Examples 1 and 6 do not satisfy ⁇ E n or ⁇ E n + ⁇ S after PCI as defined in the invention and are poor in the durability.
  • Comparative Examples 6 and 7 are small in the intrinsic viscosity, so that the tensile strength is low.
  • cords composed of high-stress spun fibers in Comparative Examples 2-4 satisfy the fiber properties and twisting structure as defined in the invention, but cannot satisfy ⁇ E n after PCI because the internal pressure in PCI is insufficient. Furthermore, the durability against crack at belt end is fairly poor as compared with the case of Examples 1 and 2.
  • Comparative Examples 8, 12 and 13 do not satisfy the fiber properties as defined in the invention, and particularly Comparative Examples 8 and 12 are outside the range of ⁇ E n or ⁇ E n + ⁇ S. Comparative Examples 9-11 satisfy the fiber properties and NT, but ⁇ E exceeds 4.5% because the internal pressure in PCI is insufficient. The tires of these comparative examples are poor in the durability.
  • T' m is a tension of cord per unit denier (kg/denier, cord)
  • D is a total denier
  • ⁇ is a carcass tension coefficient represented by ##EQU3##
  • N', i, R m , R r and R v are numerical values inherent to the kind of the tire used as shown in the following Table 3, which are put into the equation (I) or (II) to obtain the tire cord tensions T m and T' m shown in Table 3 corresponding to the internal pressure P in PCI. And also, ⁇ E n and ⁇ S corresponding thereto are shown in Table 3.
  • FIG. 2 The relation between the internal pressure in PCI and ⁇ E n based on the results of Table 3 is plotted in FIG. 2, wherein a curved line A shows the case of the tire having a size of 165 SR 13, a curved line B shows the case of the tire having a size of 185 SR 14, and numerals attached to each line are numerical values of T' m .
  • the internal pressure in PCI is dependent upon the size of the tire as apparent from FIG. 2.
  • the polyester fiber cords satisfying all features of the invention are applied to the carcass of the radial tire, the concentration of stress strain in ends of the carcass and belt can be reduced, whereby the durability of the tire can be considerably improved.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Textile Engineering (AREA)
  • Tires In General (AREA)
  • Heating, Cooling, Or Curing Plastics Or The Like In General (AREA)
  • Artificial Filaments (AREA)
  • Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
US06/700,344 1982-10-21 1985-02-13 Pneumatic radial tires Expired - Lifetime US4628978A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP57-184816 1982-10-21
JP57184816A JPS5975804A (ja) 1982-10-21 1982-10-21 高耐久性ラジアルタイヤ

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US06541633 Continuation 1983-10-13

Publications (1)

Publication Number Publication Date
US4628978A true US4628978A (en) 1986-12-16

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ID=16159785

Family Applications (1)

Application Number Title Priority Date Filing Date
US06/700,344 Expired - Lifetime US4628978A (en) 1982-10-21 1985-02-13 Pneumatic radial tires

Country Status (5)

Country Link
US (1) US4628978A (enrdf_load_stackoverflow)
JP (1) JPS5975804A (enrdf_load_stackoverflow)
AU (1) AU543534B2 (enrdf_load_stackoverflow)
DE (1) DE3337349A1 (enrdf_load_stackoverflow)
GB (1) GB2128557B (enrdf_load_stackoverflow)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5115854A (en) * 1986-02-21 1992-05-26 Bridgestone Corporation Low rolling resistance pneumatic radial tires having an improved appearance
US6345658B1 (en) * 1996-02-02 2002-02-12 The Yokohama Rubber Co., Ltd. Pneumatic radial tire with specified carcass strength coefficient
US6660212B1 (en) 2000-11-17 2003-12-09 The Goodyear Tire & Rubber Company Constrained post cure inflation
US6908587B1 (en) 2000-11-17 2005-06-21 The Goodyear Tire & Rubber Co. Post cure correction of tire uniformity
US20120247639A1 (en) * 2009-12-18 2012-10-04 Bridgestone Corporation Pneumatic tire
US20140110035A1 (en) * 2011-06-14 2014-04-24 Bridgestone Corporation Pneumatic tire
CN104089974A (zh) * 2014-07-29 2014-10-08 盐城纺织职业技术学院 合成纤维热缩率检测方法及其检测装置
US20160082784A1 (en) * 2013-05-07 2016-03-24 Sumitomo Rubber Industries, Ltd. Pneumatic tire

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59186702A (ja) * 1983-03-30 1984-10-23 Bridgestone Corp 空気入りラジアルタイヤ
JPH0717125B2 (ja) * 1984-09-17 1995-03-01 株式会社ブリヂストン 空気入りタイヤ
JPS61188204A (ja) * 1985-02-13 1986-08-21 Sumitomo Rubber Ind Ltd ラジアルタイヤ
JPS62146702A (ja) * 1985-12-20 1987-06-30 Bridgestone Corp 空気入りラジアルタイヤ
US5474836A (en) * 1993-01-06 1995-12-12 Teijin Limited Polyester filament woven fabric for air bags
EP0655351B1 (en) * 1993-11-30 1997-07-16 Bridgestone Corporation A pneumatic tire

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3616832A (en) * 1968-12-24 1971-11-02 Teijin Ltd Rubber articles reinforced with filaments
US3854515A (en) * 1972-06-28 1974-12-17 Bridgestone Tire Co Ltd Radial tire having polyester cord breaker
US3956443A (en) * 1973-07-26 1976-05-11 Uniroyal Inc. Method for cooling tires during post-inflation
US4043985A (en) * 1971-12-14 1977-08-23 Hoechst Aktiengesellschaft Tire monofilaments
US4101525A (en) * 1976-10-26 1978-07-18 Celanese Corporation Polyester yarn of high strength possessing an unusually stable internal structure
US4195052A (en) * 1976-10-26 1980-03-25 Celanese Corporation Production of improved polyester filaments of high strength possessing an unusually stable internal structure
JPS57144106A (en) * 1981-03-04 1982-09-06 Toyo Tire & Rubber Co Ltd Pneumatic tire of high uniformity
JPS57154410A (en) * 1981-03-13 1982-09-24 Toray Ind Inc Polyethylene terephthalate fiber and its production
US4420453A (en) * 1980-08-13 1983-12-13 The General Tire & Rubber Company Method of making polyester cord radial tires

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1089998B (de) * 1956-01-21 1960-09-29 Hoechst Ag Verfahren zur Kontrolle der Gleichmaessigkeit der molekularen Vororientierung von aus linearen Polyestern gesponnenen Faeden
NL128092C (enrdf_load_stackoverflow) * 1959-06-26
CA725535A (en) * 1962-01-02 1966-01-11 A. Chantry William Spinning polyester at low tension and drawing at increased temperature
US3637910A (en) * 1968-09-09 1972-01-25 Teijin Ltd Process for the preparation of fiber-forming aromatic polyesters of low free carboxyl group contents
DE2161967C3 (de) * 1971-12-14 1984-07-26 Hoechst Ag, 6230 Frankfurt Verfahren zur Herstellung eines Drahtes aus hochmolekularen, linearen Polyestern
JPS5039778A (enrdf_load_stackoverflow) * 1973-08-15 1975-04-12
JPS57154411A (en) * 1981-03-16 1982-09-24 Toray Ind Inc Polyester fiber
JPS57156050A (en) * 1981-03-20 1982-09-27 Matsushita Electric Ind Co Ltd Recovery device for ferromagnetic metal

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3616832A (en) * 1968-12-24 1971-11-02 Teijin Ltd Rubber articles reinforced with filaments
US4043985A (en) * 1971-12-14 1977-08-23 Hoechst Aktiengesellschaft Tire monofilaments
US3854515A (en) * 1972-06-28 1974-12-17 Bridgestone Tire Co Ltd Radial tire having polyester cord breaker
US3956443A (en) * 1973-07-26 1976-05-11 Uniroyal Inc. Method for cooling tires during post-inflation
US4101525A (en) * 1976-10-26 1978-07-18 Celanese Corporation Polyester yarn of high strength possessing an unusually stable internal structure
US4195052A (en) * 1976-10-26 1980-03-25 Celanese Corporation Production of improved polyester filaments of high strength possessing an unusually stable internal structure
US4420453A (en) * 1980-08-13 1983-12-13 The General Tire & Rubber Company Method of making polyester cord radial tires
JPS57144106A (en) * 1981-03-04 1982-09-06 Toyo Tire & Rubber Co Ltd Pneumatic tire of high uniformity
JPS57154410A (en) * 1981-03-13 1982-09-24 Toray Ind Inc Polyethylene terephthalate fiber and its production

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5115854A (en) * 1986-02-21 1992-05-26 Bridgestone Corporation Low rolling resistance pneumatic radial tires having an improved appearance
US6345658B1 (en) * 1996-02-02 2002-02-12 The Yokohama Rubber Co., Ltd. Pneumatic radial tire with specified carcass strength coefficient
US20020043321A1 (en) * 1996-02-02 2002-04-18 Zenichiro Shida Pneumatic radial tire
US6834700B2 (en) 1996-02-02 2004-12-28 The Yokohama Rubber Co., Ltd. Pneumatic radial tire with specified carcass strength coefficient
US6660212B1 (en) 2000-11-17 2003-12-09 The Goodyear Tire & Rubber Company Constrained post cure inflation
US6908587B1 (en) 2000-11-17 2005-06-21 The Goodyear Tire & Rubber Co. Post cure correction of tire uniformity
US20120247639A1 (en) * 2009-12-18 2012-10-04 Bridgestone Corporation Pneumatic tire
CN102791497A (zh) * 2009-12-18 2012-11-21 株式会社普利司通 充气轮胎
US9033017B2 (en) * 2009-12-18 2015-05-19 Bridgestone Corporation Pneumatic tire
US20140110035A1 (en) * 2011-06-14 2014-04-24 Bridgestone Corporation Pneumatic tire
US20160082784A1 (en) * 2013-05-07 2016-03-24 Sumitomo Rubber Industries, Ltd. Pneumatic tire
US10112445B2 (en) * 2013-05-07 2018-10-30 Sumitomo Rubber Industries, Ltd. Pneumatic tire
CN104089974A (zh) * 2014-07-29 2014-10-08 盐城纺织职业技术学院 合成纤维热缩率检测方法及其检测装置

Also Published As

Publication number Publication date
JPS6339442B2 (enrdf_load_stackoverflow) 1988-08-05
DE3337349A1 (de) 1984-04-26
GB2128557B (en) 1986-03-12
GB8327240D0 (en) 1983-11-16
AU543534B2 (en) 1985-04-26
AU1991183A (en) 1984-05-10
JPS5975804A (ja) 1984-04-28
GB2128557A (en) 1984-05-02
DE3337349C2 (enrdf_load_stackoverflow) 1989-07-06

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